Raymond Yau <superquad.vortex2 at gmail.com> [2015-04-19 10:47:11 +0800]: > > You have not posted alsa-info of working 3.18 > Here are alsa-info.sh reports for both kernels: http://misc.postpro.net/t510led/alsa_info_3.18.6.txt http://misc.postpro.net/t510led/alsa_info_3.19.3_soft0.txt http://misc.postpro.net/t510led/alsa_info_3.19.3_soft1.txt The difference between the 3.19 "soft0" and "soft1" versions is that "soft0" version was booted with the kernel commandline parameter thinkpad_acpi.software_mute=0 This just reverts the muting behavior back to 3.18 (which is my preference). The "soft1" version does not supply this parameter, so you get the default 3.19 behavior (i.e., software muting enabled, HW muting disabled.) > > Refer to alsa-info found in t510 speaker powersave regression > > https://lkml.org/lkml/2012/12/22/113 > Superficially, to my eyes anyway, it doesn't seem related to this issue. Do you think it might be? If so, please be more explicit, I don't see the connection. > > Simple mixer control 'Console',0 > Capabilities: pswitch pswitch-joined > Playback channels: Mono Mono: Playback [on] > > Do this console playback switch has any effect on your schematic view ? > It's a read-only card, so it has no "effect", but its state does reflect the HW mute state. See further below for details. > > AFAIK, pulseaudio ignore card 29 "ThinkPadEC" > Yes, that seems to be right. But it can be seen via amixer -c29: Here's the observed behavior under 3.18, using the terminology from the kernel bug report: 0. Toggle MUTEKEY until MUTELED = off. 1. Start audio source, verify SPK_SOUND = on 2. 'amixer -c29 get Console' reports "Mono: Playback [on]" 3. Toggle MUTEKEY, verify MUTELED = on, SPK_SOUND = off 4. 'amixer -c29 get Console' reports "Mono: Playback [off]" That's all I see.